Xinjiang Uygur autonomous region authorities yesterday denied media reports that two people were detained after one of them set fire to toilet paper in the lavatory on a flight taking off from regional capital Urumqi during the weekend.

"Only one person was detained for smoking in the toilet, not for setting fire to toilet paper as some media reported. The second person was taken away by police because the two were traveling together," regional spokesperson Hou Hanmin told China Daily yesterday.

The Xinhua News Agency reported on Saturday that the crew of China Southern flight CZ6939 discovered that a passenger had allegedly set fire to toilet paper in the lavatory, which triggered the fire alarm.

The flight, which was bound for Wuhan, capital of Hubei province, via Xi'an, capital of Shaanxi province, was forced to turn around and a woman and a man were taken away by local police after the flight landed at Urumqi's international airport.

The passenger who broke aviation laws for smoking onboard a flight received 15 days' administrative detention and was fined 1,000 yuan ($150), the Xinjiang public security department said yesterday, without specifying the gender of the offender.

"The passengers onboard CZ6939 were informed that the flight had to return to Urumqi due to technical fault about two hours into the journey," said a reporter with the Wuhan-based Chang Jiang Daily who was on the same flight as the two suspects.

When the reporter got off the plane at 11:40 am on Saturday, he noticed that a middle-aged man with a knitted hat who sat at 10B of the Boeing 737-700 aircraft was held by a crew member and he looked "very anxious".

A passenger who sat at 11C saw a middle-aged woman with a headscarf sitting in front of him get up for the toilet five minutes into the journey with no sign of her returning to her seat, the reporter said.

He was later told that a crew member noticed smoke coming out from a toilet on the right side of the aircraft, which soon turned around.

The flight took off again at 3:10pm and landed at its final destination, the Wuhan Tianhe Airport. The airline apologized for the disruption and said it was due to "some passengers' personal reasons".

According to a source with China Southern airlines, the detained passenger used matches carried onto the flight to light the cigarette.

But the Urumqi international airport authorities did not need to tighten security checks because of the latest incident as the system is up to national standards, an airport staff said yesterday.

In China, it is prohibited to carry lighters, matches and other combustible materials onto any domestic or international flight.